It can run Mac software for 68k machines and has versions for Windows, Linux and DOS. Originally a commercial product, Executor was released as freeware and open-sourced by the authors in 2008-2009. But recently I learned about an emulator (or rather, a compatibility layer) called Executor which does not have these requirements.
There exist a number of free, open source Macintosh emulators (a good overview can be found at this site), however nearly all of them require a ROM image obtained from an actual Mac and a copy of MacOS to run. And even though a Mac demo was released by Blizzard, running it without a Mac is not possible. However, apparently it is almost impossible to find any good quality screenshots of the Mac version on the net these days. The Mac version of Warcraft: Orcs & Humans also got a graphics upgrade, as is evident from these reviews (preserved by the Wayback Machine):
This is why some Mac ports of PC or console titles received updated graphics to match the increased resolution compared to the originals. In the early-mid 90s, when the default screen resolution for many DOS games was 320x200, Macintosh computers already used 640x480 by default.
